Whitney Houston in Rehab for Drug and Alcohol Treatment

The singer, 47, who has struggled with substance abuse in the past, has recently entered an out-patient treatment program.

"Whitney Houston is currently in an out-patient rehab program for drug and alcohol treatment," her rep tells PEOPLE in a statement. "Whitney voluntarily entered the program to support her long-standing recovery process."

Houston initially entered rehab in 2004, telling ABC News interviewer Diane Sawyer at the time: "I partied a lot. Trust me: I partied my tail off." But, the singer also admitted, "You get to a point where you know the party's over."